The invention relates to a pressure roll having a stationary axial supporting member and having a roll shell which can rotate about the supporting member and which is supported on the supporting member by hydrostatic supporting elements.
The pressure roll initially described is a so-called pressure equalisation roll. The shell is pressed by means of the supporting elements against at least one counter-roll appointed to the pressure rolls in a rolling mill, whereby an equal application pressure can be produced in all regions along the press gap between the co-operating rolls. The supporting elements are arranged in supporting planes each of which is defined by the axis of the supporting member or the roll shell respectively and the axis of the counter-roll. The press gap is also situated in each case in the supporting plane.
Deflection of the supporting member occurs during a pressure treatment on a web of material in the press gap under the action of the supporting elements. The roll shell is also subjected to deformation when it is adapted to deflection of the counter-roll under the pressure of the supporting elements to form a press gap of equal clearance over the entire width of the web of material.
In a three-high mill in which the axes of a pressure roll and of the counter-rolls are situated in two planes parallel to one another, the roll shell is to be adapted at the same time to the deflection of the two counter-rolls.
Since the position and shape of the roll shell and those of the supporting member continually vary relatively to one another during operation of the rolling mill, it is difficult to find a mounting for the roll shell relatively to the supporting member. Hitherto known constructions connected therewith are complicated and are not always satisfactory in all possible uses of a pressure equalisation roll. For example in the aforesaid three-high rolling mills: here the roll shell, if guided and mounted in a conventional manner relatively to the supporting member, cannot follow relatively deep deflections of the counter-rolls. This has the result that the counter-rolls also have to be constructed as pressure equalisation rolls in order to obtain a substantially straight press gap. This makes rolling mills of this kind correspondingly expensive and complicated.